Ashless lubricant additive

ABSTRACT

AN ASHLESS LUBRICANT ADDITIVE WHICH IMPROVES THE VISCOSITY INDEX. THE ANTI-CORROSION, ANTI-OXIDANT. ANTI-WEAR AND DETERGENT PROPERTIES OF THE BASE OIL. THE ADDITIVE IS THE REACTION PRODUCT OF (A) A PHOSPHOSULFURIZED ETHYLENE/1,4-HEXADIENE TERPOLYMER HAVING AN AVERAGE MULECULAR WEIGHT OF BETWEEN ABOUT 3,500 AND ABOUT 65,000 AND CONTAINING ABOUT 35-70 WEIGHT PERCENT PROPYLENE, ABOUT 1-6 WEIGHT PERCENT 1,4-HEXADIENE AND THE REMAINDER BEING ETHYLENE; WITH (B) AN AMINE OF THE FORMULA   NH2-(CH2)X-N(-R)-R1   WHEREIN X IS AN INTEGER OF 2 OR 3, AND R AND R1 ARE ALKYL GROUPOF 1-4 CARBON ATOMS.

United States Patent 3,560,384 ASHLESS LUBRICANT ADDITIVE Robert A.Halling, Wilmington, Del., assignor to E. I. du Pont de Nemours andCompany, Wilmington, Del., a corporation of Delaware No Drawing. FiledOct. 14, 1968, Ser. No. 767,486 Int. Cl. C10m 1/48 U.S. Cl. 252--46.7Claims ABSTRACT OF THE DISCLOSURE wherein x is an integer of 2 or 3, andR and R are alkyl groups of l-4 carbon atoms.

XNRRI BACKGROUND OF THE INVENTION (1) Field of the invention Thisinvention relates to an ashless lubricant additive, and moreparticularly to the product of an amine and a phosphosulfurized olefinterpolymer.

(2) Description of the prior art Ashless lubricant additives comprisingthe reaction product obtained by (a) treating polyisobutylene orpolypropylene, with P 8 (b) hydrolyzing the olefin-P 5 product, and (c)treating the hydrolyzed product with an aliphatic amine or an alkylenepolyamine have been found useful in improving the dispersancy oflubricating oils and in improving thedetergent properties of thelubricating oil (see US. 3,143,506).

More recently, an ashless lubricant additive was prepared comprising thereaction product obtained by (a) treating a low-molecular-weightpolyisobutylene (mol.- wt. 250l500) with P 3 and (b) reacting thephosphosulfurized polyisobutylene with an amine of the formulaCH2CHzNI-I wherein x is l-9 (see US. 3,329,612). These lubricantadditives are described as improving the anti-corrosion, anti-oxidantand anti-wear properties of the lubricating oil as well as improving theoils detergent properties.

However, it is sometimes necessary to add a viscosity index improver tolubricating oils containing the abovedescribed ashless lubricantadditives, inasmuch as the above-described additives do not improve theviscositytemperature characteristics of the oils to any extent.

Accordingly, it is an object of this invention to provide an ashlesslubricant additive which improves the viscosity index of the lubricatingoil as well as improving the detergent, anti-corrosion, anti-oxidant andanti-wear properties. This and other objects will be apparent ashereinafter described.

In addition to improving the viscosity index of lubricating oils, theadditives of this invention have been found to unexpectedly improve theperformance of ex- 3,560,384 Patented Feb. 2, 1971 treme pressureadditives in a compounded lubricating oil, even though they do notpossess extreme pressure properties themselves. Moreover, the additivesof this invention possess exceptionally high shear stability.

SUMMARY OF THE INVENTION This invention is directed to a lubricantadditive comprising the product obtained by reacting (A) Aphosphosulfurized ethylene/propylene/ 1,4- hexadiene terpolymer havingan average molecular Weight of between about 3,500 and about 65,000 andcontaining about 35-70 weight percent propylene, about l6 Weight percent1,4-hexadiene and the remainder being ethylene; with (B) An amine of theformula wherein x is an integer of 2 or 3, and R and R are alkyl groupsof l-4 carbon atoms.

The invention is also directed to a lubricant composition of a minerallubricating oil and from about 0.1 to about 4 percent by weight of theoil of the additive defined in the preceding paragraph.

The invention is further directed to a lubricant additive concentratecomprising a neutral lubricating oil and about 5 to about 50 percent byweight of the oil of the additive defined in the first paragraph of thissummary.

DESCRIPTION OF THE INVENTION The lubricant additive of this invention isconveniently prepared by a two-step process.

The first step comprises reacting the ethylene/propylene/ 1,4-hexadieneterpolymer with P 8 in the substantial absence of oxygen and underessentially anhydrous conditions, e.g., in an atmosphere of nitrogen orother inert gases, at a temperature of between about 200 F. and 500 F.The amount of P 8 employed is ordinarily between about 0.25 to about 5moles per mole of 1,4- hexadiene in the terpolymer. Preferably 0.5 to1.5 moles of P 8 are used. The time of reaction is normally be tweenabout 4 and about 30 hours. The use of an inert solvent, e.g., ahydrocarbon such as hexane, octane, or a halocarbon such as1,2,4-trichlorobenzene is desirable. A halocarbon such as achloroaromatic compound is preferred.

The second step comprises reacting the phosphosulfurized terpolymer,which can be used after merely decanting or filtering the reaction massof the first step to remove insoluble byproducts and unreactedreactants, with the amine. The second step is carried out at atemperature of between about 200 F. and about 500 F. for a period ofabout 4 to about 30 hours. The amount of the amine employed can rangebetween about 2 to about 6 moles of amine per atom of phosphorusemployed in the first step. The preferred amount of amine used isbetween 2 and 4 moles per atom of phosphorus. The same or a differentsolvent as used in the first step can be employed in this second step.When the same solvent is used in both steps the reaction mass of thefirst step can be employed directly. The final product is ordinarilyisolated by usual methods, as for example by precipitating withmethanol. However, if the solvent employed in the reaction sequence iscompatible with the lubricating oil, the final mixture need only befiltered, or at most, needs only a water wash followed by drying. Theproduct, if isolated, may be purified by extraction with methanol,followed by drying.

The pressure employed in the reaction is preferably atmospheric,although superor subatmospheric pressures may be used.

The terpolymers employed in the composition of this invention areamorphous polymers which can contain 35-70 weight percent propylene, 16weight percent 1,4-hexadiene with the remainder ethylene. Preferredweight percent ranges are 42-55 weight percent propylene, 1-4 weightpercent 1,4-hexadiene with the remainder ethylene. Preferably theterpolymers should have a relatively narrow molecular weightdistribution. The molecular weight distribution, which is determined bydividing the weight average molecular weight by the number averagemolecular weight, should be less than 8.

Suitable copolymers are the essentially amorphous, oil solublecopolymers of ethylene which are prepared by polymerization in thepresence of coordination catalysts. Polymerization with these catalystsis well known, as described, for example, in U.S. 2,799,668, 2,975,159and 2,933,480. Since the utilization of these catalysts can produce avariety of polymers from ethylene and propylene, it is important tocontrol the conditions of the reaction in order to obtain the specificamorphous polymers useful in the invention having specified molecularweights and a narrow molecular weight distribution.

More specifically, in order to obtain the amorphous copolymers desired,it is advantageous touse a hydrocarbon soluble vanadium compound, e.g.VOCl or vanadium triacetylacetonate, in combination with an alkylaluminum chloride as described by Natta et al. in U.S. 3,300,459 and inJ. Polymer Sci, 51, 411ff and 429ff (1961). Use of this catalyst systemresults in essentially amorphous copolymers soluble in a minerallubricating oil. Such copolymers exhibit substantially no crystallinityas evidenced by X-ray examination.

The effectiveness of the subject copolymers as viscosity index improverslies also in the controlled molecular weight range and narrowdistribution of the molecular Weight. This can be achieved by methodsdescribed by Natta in J. Polymer Sci, 34, 5411f (1959), e.g. by the useof chain transfer agents such as metal alkyls, esp. Zinc alkyls, and byuse of hydrogen pressure, U.S. 3,051,690. The article by Natta abovecited, J. Polymer Sci., 51, 411 (1961), also described the operativeconditions for the preparation of such polymers, such as time,temperature, catalyst concentration and monomer concentration.

As is well known, these catalysts must be used in strict absence ofoxygen, water or other material with which they react. For this reasonthe solvents in which they are used are greatly limited, the preferredones being the saturated aliphatic and hydroaromatic hydrocarbons andcertain nonreactive halogen compounds such as tetrachloroethylene andchlorobenzenes. These compounds conveniently serve as solvents for thepolymerization which ,is usually carried out in a dilute suspension ofthe catalyst. The polymerization is normally carried out at ordinarytemperatures and pressures. The inherent viscosity range of theterpolymer is between about 0.1 and 1 as measured as a 0.1 weightpercent solution in tetrachloroethylene at 30 C. The range of 0.1 to 1.0corresponds to about 3,500 to 65,000 weight average molecular weight asdetermined by light scattering. Preferred terpolymers have an inherentviscosity of 0.1 to 0.6, correspond to 3,500 to 35,000 weight averagemolecular weight.

Amines suitable for use in this invention are those of the formulawherein x is 2 or 3 and R and R are the same or different alkyl groupsof 1-4 carbon atoms. Preferably R and R are the same. Representativesuitable amines include N,N- dimethyl-1,3-propanediamine,N,N-dimethylethylenediamine, N,N-diethyl-1,3-propanediamine,N,N-diethylethylenediamine, N,N-dipropyl-1,3-propanediamine, N,N-di- 4propylethylenediamine, N,N-dibutyl-1,3-propanediamine,N,N-dibutylethylenediamine, and the like.

The reaction product formed as described previously does not have adefinite stoichiometric relationship between the phosphorus, sulfur andnitrogen atoms present. Hence the reaction product of this invention isbelieved to be a mixture of products.

The reaction product is useful, as stated previously, as an additive forimproving the properties of mineral or neutral lubricating oils, such ascrankcase oils, automotive transmission fluid base oils or hydraulicfluid base oils. Lubricating oils and transmission fluids arepredominantly parafiinic, solvent-refined neutral oils having SayboltUniversal Seconds (S.U.S.) viscosities of about to 220 at 100 F. andviscosity indices of about to 110. For use with the additives of thisinvention, preferred lubricating oils should have S.U.S. viscosities ofabout to 160, while preferred transmission fluids should have S.U.S.viscosities of about 60 to 110. Hydraulic fluid base oils arepredominantly naphthenic, solven-refined neutral oils having S.U.S.viscosities of not greater than about 50 and pour points not over 65 F.

Effective amounts of the additive of this invention are employed withthe mineral or neutral oils, usually between about 0.1 to 4 percent byweight of the oil and preferably 5 viscosity at F. If desired, solutiontime may be decreased by preheating the oil to -210 F. before milling orblending.

The following examples describe the preparation of the additives andtheir usefulness in greater detail, and are 40 meant to berepresentative rather than limiting. All parts are by weight unlessotherwise indicated.

EXAMPLE A A typical terpolymer preparation is as follows: Ethylene,propylene and 1,4-hexadiene are polymerized in an evaporatively cooled,continuous flow, stirred reactor operated at 30 C. The partial pressuresand flow rates of the monomers are adjusted to obtain the desiredcomposition. The terpolymers used in the examples which follow were madein hexane solution in the presence of a coordination catalyst formed insitu by combining diisobutyl aluminum monochloride with vanadiumtris(acetylacetonate). The partial pressure of hydrogen in the reactorwas 15.6 lb./sq. in. (absolute) and the residence time was 36.3 minutes.

EXAMPLE 1 Preparation of additive In 1800 ml. of 1,2,4-trichlorobenzenewith a dry nitrogen atmosphere about it were reacted 100 g. (0.043 moleas 1,4-hexadiene) of an ethylene, propylene, 1,4-hexadiene terpolymerhaving a wt. ratio of E61.7/P34.9/ HD-3.4 and an inherent viscosity of0.44 (as measured on a 0.1 wt. percent solution in tetrachloroethyleneat 30, about 23,000 mol. wt.) and 20 g. (0.09 mole) P 5 at a temperatureof 200-210 C. for a period of 6 hours. The reaction mixture was cooledand the insoluble residue was removed by decanting the solution. To thesolution was added 51 g. (0.5 mole) N,N-dimethyl-1,3-propanediamine. Thetemperature was raised slowly to 205- 210 C. over a 4-hour period andthe mixture was allowed to stir at that temperature for 6 hours. Aftercooling, the reaction mixture was poured into 23 times its volume ofmethanol to precipitate the reaction product. The precipitated reactionproduct was repeatedly extracted with methanol in a high-speed blenderuntil trichlorobenzene was completely removed and was finally vacuumdried. The reaction product contained 1.8 weight percent phosphorus, 2.8weight percent sulfur, and 1.1 weight percent nitrogen.

EXAMPLE 2 Preparation of additive A reaction product containing 1.0weight percent phosphorus, 1.5 Weight percent sulfur, and 0.51 weightpercent nitrogen was prepared using a mole ratio of 1/1/10 of the sameterpolymer used in Example 1/P S /N,N-dimethyl-1,3-propanediamineingredients under the same reaction conditions as described in Example1.

EXAMPLE 3 Preparation of additive A reaction product containing 2.4weight percent phosphorus, 3.5 weight percent sulfur, and 1.8 weightpercent nitrogen was prepared using a mole ratio of terpolymer (54%E/42% P/4.1% 1,4-HD and inherent viscosity of 0.44) /P S/N,N-dimethyl-1,3-propanediamine of 1/4/ 16 under the same reactionconditions of Example 1.

EXAMPLE 4 Preparation of additives A reaction product containing 1weight percent phosphorus, 1.4 weight percent sulfur, and 0.52 weightpercent nitrogen was prepared using a mole ratio of terpolymer (59.7%E/37.9% P/2.4% 1,4-HD and inherent viscosity of 0.59)/P S/N,N-dirnethyl-1,3-propanediamine of 1/1/10 under the same reactionconditions of Example 1.

EXAMPLE 5 Viscosity properties This example shows that the reactionproducts of this invention possess the thickening properties requiredfor use as a viscosity index improver in multigraded lubrieating oils.

The products of Examples 1 and 2 were each added to refined 131 neutraloil S.U.S. at 100 F. to result in compositions containing 1, 2 and 3percent by total weight. The thickening, as measured in terms of'viscosity, resulting from the addition of the stated amounts ofadditive is shown in the following Table A:

The measurement of cs. (centistokes) at 210 F. was carried out by ASTMTest Method D445.

The measurement of p. (poise) at 0 F. was measured using a cold crankingsimulator. A universal motor, run at constant voltage, drives a rotorwhich is closely fitted inside a stator. A small portion of theoil/additive composition fills the space between the rotor and statorwhich are maintained at 0 F. The speed of the rotor is a function of,and is calibrated to determine the viscosity of the oil/additivecomposition in poises.

The slope was obtained by ASTM Test Method D341.

Table A shows that the additives of this invention, in an amount of 1weight percent, increase the viscosity of the oil as measured in cs. at210 F. by about 30 percent; while an amount of 3 weight percentincreases the viscosity by about 170 percent.

6 EXAMPLE 6 Shear stability The shear stabilities of oil compositionscontaining the same base oil as in the viscosity index test of Example 5and the amount of various ethylene teipolymers necessary to increase theviscosity of the oil composition to 11.5:t0.1 centistokes at 210 F. weredetermined using a 250 W., 10 kc. magnetostrictive sonic oscillator inaccordance with the technique described in Proposed Method of Test forShear Stability of Polymer-Containing Oils, in ASTM Standards, vol. I,page 1160 (October 1961). The procedure was modified by shearing a 50ml. sample for 60 minutes at F. at 0.6 r.f. amps. Shear stability isexpressed as the average percent retention of viscosity in Table B showsthat the shear stability of the additives of this invention issubstantially maintained.

EXAMPLE 7 Dispersancy power Low temperature deposition tests in a singlecylinder CLR engine for 180 hours according to the procedure of FTM-79laMethod 348 Modified were carried out. Lubricating oil compositionslabeled A, B, and C were tested. Each composition contained lubricatingoil, zinc dialkyldithiophosphate and a high-base calcium sulfonate (eachadded to provide rust-inhibition and antioxidant properties to the oil).The ingredients of compositions A, B, and C are listed as follows:

A Ingredients (control) B C SAE-BO base oil (618.8 S.U.S. at 100 F.)Zinc dialkyldithiophosphate, wt., percent- 1 1 1 High-base calciumsulfonate, wt., percent 2 2 2 Additive of Example 1, wt. percent... 2Additive of Example 4, wt, percent. 2

Prescnt.

The results are shown in Table C, as follows, in which a rating of 10represents maximum cleaning of the piston skirt and a rating of 50represents maximum cleaning of Total and of CRC Sludge:

TABLE C.-RATINGS Percent clogging Varnish Piston 0 RC screen, Oil ring,Composition skirt Total sludge percent percent A (control) 6 35 37 30 51B 7. 7 44 48 5 18 C 8. 0 37 44 10 1 1 10W-50 base oil (131 S.U.S. at 100F.).

The results of Table C show that the oil additives of this inventionimprove dispersancy in low-temperature deposition tests.

EXAMPLE 8 Anti-rusting properties The anti-rust properties of theadditives of this invention were determined by placing 30 ml. of an oilblend of compositions A-C, described below, in 4-02. jars along with 3ml. of synthetic exhaust condensate and a SAE 1020 carbon steel billet.The mixture was heated for 24 hours at F. The billet was removed, rinsedwith a hydrocarbon solvent and examined for the percent area rusted.

The composition of the oil blends and the results obtained using themare shown in Table D as follows:

TABLE D Percent area Composition: rusted (A) IOW-SO base oil (131 S.U.S.at 100 F.) Over (B) Base oil of A above and 2 weight percent of theadditive of Example 4 Less than 1 (C) Base oil of A above and 2 weightpercent of the additive of Example 1-- Less than 1 Table D clearly showsthe anti-rust properties of the compositions of this invention.

EXAMPLE 9 Antioxidant and bearing corrosion inhibition propertiesProducts of this invention were evaluated for their lube oil antioxidantand bearing corrosion inhibition properties in the MacCoull OxidationTest. The MacCoull Test is a method of determining the oxidationstability and corrosive effect of lubricating oils on a copper-leadbearing. The test, a modification of the method originally developed byThe Texas Co. (Method SP148-48, Feb. 1, 1948), is carried out so as toreproduce the oil-bearing conditions which actually exist in an engine,namely, circulation of the oil through a rotating bearing, contact withother metal surfaces and air, and recirculation through the bearing. Theoil sample being tested is oxidized at a temperature of 350 F. After 10hours of operation, each bearing weight is subtracted from itscorresponding original weight. The difference, reported in milligrams,is known as the bearing weight loss. The degree of bearing corrosion bythe oil is indicated by the amount of bearing weight loss, anon-corrosive oil showing little or no bearing weight loss and,conversely, a highly corrosive oil showing a much greater bearing weightloss.

The antioxidant properties were measured by the change in the total acidnumber before and after the test. Total Acid Number, Total Base Number,and Viscosity tests are run on the oil in order to obtain a measure ofits resistance to oxidation. The relative increase in total acid numberand viscosity, and the decrease in total base number are indicative ofoxidation of the oil.

In the absence of any other additives in the oil blend, the products ofthis invention caused a decrease in the amount of oxidation of the oil,over the amount occurring in the oil with no additives in it. In thepresence of other commercial anti-oxidants, the level is decreased evenfurther, showing that there are no incompatibility problems to beconcerned with. Another feature of the additives of this invention isthat, in combination with a commercial antioxidant, zincdialkyldithiophosphate and a high-base calcium petroleum sulfonate, ahigh percent of the basicity is retained. This indicates that theadditives of this invention possess long detergent life.

The results obtained are described in Table E as follows:

8 EXAMPLE 10 Antiwear properties ASTM Test Method D267 0-67 StandardMethod for measuring Wear properties of fluid lubricants (Falex Method)The Falex Wear test was used to evaluate the antiwear properties of theadditives of this invention. In this standard load/wear test, the steelbushings Were SAE 4615 4620, 90 minimum Rockwell B, 15 RMS maximum. Thesteel pen was Sanderson special drill rod, 98 102 Rockwell B, RMSmaximum. In the Table F below, the oil compositions employed weremixtures of Solvent 131 SUS neutral and the additive indicated. Theresults are shown as follows:

TABLE F.FALEX WEAR TEST [Oil=Solvent refined neutral oil, 131 S.U.S. at100 F.]

Wear at 1,000 lbs/ min.

Load Scar (11).) at Total, width, Additive uscd seizure mg. mm.

None 2, 350 1 wt. percent zinc dialkyldithiophospliate, a commercialadditive 1, 400 04. 1 1. 25 2 wt. percent product of Example 2 2, 275 O.8 0. 38 2 wt. percent product of Example 2, 600 0.6 0.38

1 Seizure.

As shown by the table, the additives of this invention impart superiorantiwear properties to the oil.

EXAMPLE 11 Load-carrying capacity test (Mean-Hertz Load).The

, terpolymer-P S -diamine additives of this invention were evaluated ina four-ball extreme pressure test. Since these additives exhibited verygood antiwear properties, it was expected that they would also possesssome Extreme Pressure properties. Frequently these two properties arefound in the same additive. That was not the case with these products.The results of this test (Table G) show that they do no possess anyExtreme Pressure properties in themselves. Surprisingly, however, whentested in com bination with a commercial zinc dithiophosphate-typeExtreme Pressure additive, the additives of this invention greatlyenhance the Extreme Pressure properties of the zinc dithiophosphateadditive, as shown by an increase in the Mean Hertz Load from 38 to 54kilograms (in Table G). This synergistic effect was dependent upon theconcentration of the zinc dithiophosphate. When the zinc dithiophosphateconcentration was decreased from 1 to 0.5 percent, the Extreme Pressureproperties decreased as well.

The test was carried out with a 10-second test duration at each appliedload. The Mean Hertz Load is calculated from the series of scardiameters. The Point of Incipient Seizure is the highest load at whichthe scar diameter in- TABLE E.M.-\CCOULL OXIDATION TEST (10 HOURS AT350F.)

Oil A=Solvent refined neuztral oil 131 SUS at 100 F Oil B =0i1 A 1 Wt.percent zinc dialkyldithiophosphate 2 wt. percent high-base calciumsulfonate.

ASTM test method viscosity (D 445) mg. KOH/g.

210 F. 100 F. TAN-E TBN-E B a1" Composition, oil plus additive 1V5. ltis s (2 wt. percent) Initial Final Initial Final Initial Final InitialFinal mg. A plus none 4. 76 7. 95 27. 3 64. 4 04 11. 3 0 0 63 A plusproduct of Example 4 9. 41 7. 86 63. 8 54. 2 0. 1 3. 6 0. 2 0 18 A plusproduct of Example 2 8.01 7. 31 51. 7 48. 5 1. 2 2. 2 0. 1 O 19 B plusproduct of Example 4 9. 93 15. 99 70. 1 118. 2 2. 0 1. 7 5. 5 1. 9 5 Bplus product of Example 2 8. 18 10. 31 54. 5 69. 4 1. 9 1. 6 5. 9 1. 4 5

The table shows that the presence of additives of this invention retardsoxidation of the oil and reduces corrosion on bearings.

dicates that the oil is still functioning in the region of full fluidfilm lubrication. The scar diameters at loads above this point show theperformance of the oil in the area of thin film or boundary lubrication.The weld point is the load at which the four balls weld or at which thescar diameter exceeds 2.5 mm. The results are described in Table G, asfollows:

TABLE G.-LOAD-CARRYING CgAPACITY (FTM 7913 METHOD 65 [Oil-Solventrefined neutral oil 131 SUS. at 100 F.]

Point of Mean Weld incipient hertz point, seizure, load, Additive usedin the oil kg. kg. kg.

None 71 40 15. 9 1 wt. percent zine dialkyldithiophosphate (A) 112 7138. 2 1 wt. percent (A) plus 2 wt. percent highbase calcium sulfonate(B)- 141 63 32. 4 2 wt. percent product of Example 4... 79 50 20. 2 2wt. percent product of Example 1... 71 40 16. 1 1 wt. percent (A) plus 2wt. percent product of Example 4 112 79 40. 1 1 wt. percent (A) plus 2wt. percent product of Example 1 158 112 53. 9 0.5 wt. percent (A) plus2 wt. percent product of Example 1 178 79 39. 6 1 wt. percent (A) plus 2wt. percent (B) plus 2 wt. percent product of Example 1 158 100 47. 9

The foregoing examples demonstrate that the terpolymer-P S -amineadditives of this invention are truly multifunctional additives. Theypossess surprisingly good Vis cosity Index improving properties. Theyalso show an unexpected synergistic eifect on extreme pressureproperties when used with a commercial zinc dialkyldithiophosphateadditive. In addition they have excellent lowtemperature detergent,antioxidant, bearing corrosion inhibition, antirusting and antiwearproperties. At an average use concentration of 2 wt. percent in thelubricating oil, the desired level of performance in each of the aboveproperties can be achieved with only the single additive of theinvention. This results in simplification for the refiner in formulatinga complete crankcase lubricating oil. In addition, the additive isashless.

The foregoing detailed description has been given for clearness ofunderstanding only and no unnecessary limitations are to be understoodtherefrom. The invention is not limited to the exact details shown anddescribed, for obvious modifications will occur to those skilled in theart.

10 The embodiments of the invention in which an exclusive property orprivilege are claimed are defined as follows:

1. A lubricant additive consisting essentially of the product obtainedby reacting (A) a phosphosulfurized ethylene/propylene/1,4hexadieneterpolymer having an average molecular weight of between about 3,500 andabout 65,000 and containing about 35-70 weight percent propylene, about1-6 weight percent 1,4-hexadiene and the remainder being ethylene; with(B) an amine of the formula H N(CH NRR wherein x is an integer of 2 or3, and R and R are alkyl groups of 1-4 carbon atoms.

2. The additive of claim 1 in which the terpolymer contains 42-55 weightpercent propylene, 1-4 weight percent 1,4-hexadiene with the remainderethylene and in which the molecular weight is between about 3,500 and35,000.

3. The additive of claim 2 in which the amine isN,N-dimethyl-l,3-propanediamine.

4. A lubricant additive concentrate comprising a lubricating amount of aneutral lubricating oil and about 5 to about 50% by weight of theadditive of claim 1.

5. A lubricant composition comprising a lubricating amount of a minerallubricating oil and from about 0.1

to about 4% by weight of the additive of claim 1.

References Cited UNITED STATES PATENTS DANIEL E. WYMAN, Primary ExaminerW. H. CANNON, Assistant Examiner U.S. Cl. X.R.

